Could you test version of the xbmc posted on the following URL with the lastest drivers?
XBMCSetup-20130912-596f548.exe - Google Drive
Also please add (or change if it's exists) %APPDATA%\XBMC\userdata\advancedsettings.xml with following lines
<advancedsettings>
<video>
<dxvausehdprocessor>true</dxvausehdprocessor>
</video>
</advancedsettings>
Thanks.
